MySQL Functions
- Functions are used to perform some specific task.
- Every functions has a particular pre-defined tasks.
- functions are categorized into two parts.
1. Single Row Functions
- These functions operates on a single row at a time.
- These functions are categorized into following parts-
i. Math Functions
ii. String Functions
iii. Date and Time functions etc.
2. Multi Row / Aggregate Functions
- These functions operates on multiple rows simultaneously.
- Some of the Aggregate Functions are-
| Function | Purpose | Syntax | Example |
|---|---|---|---|
| COUNT() | Counts number of rows (ignores NULL) | SELECT COUNT(column_name) FROM table; |
SELECT COUNT(ID) FROM STUDENT; |
| SUM() | Returns total sum of numeric column | SELECT SUM(column_name) FROM table; |
SELECT SUM(Marks) FROM RESULT; |
| AVG() | Returns average of numeric column | SELECT AVG(column_name) FROM table; |
SELECT AVG(Salary) FROM EMPLOYEE; |
| MIN() | Returns smallest value in the column | SELECT MIN(column_name) FROM table; |
SELECT MIN(Price) FROM PRODUCT; |
| MAX() | Returns largest value in the column | SELECT MAX(column_name) FROM table; |
SELECT MAX(Score) FROM EXAM; |
